The invention relates to a method of sterilizing dried good such as dried herbs, spices, teas, drugs and remedies by introducing a gas into a sealed container receiving the goods for destroying adult organisms as well as larvae and eggs thereof.
In an article by the authors Egon Stahl, G. Rau and H. Adolphi printed in the magazine "Die Pharmazeutische Industrie" (Pharm. Ind. 47, 5, 528 to 530 (1985)), the following is stated: "To some degree drugs (herbs) are always contaminated by harmful insects, larvae or eggs. As agents for destroying the insects, larvae and eggs, phosphine, ferrocyanide and methylbromide are utilized. Use of these gases is limited however because they are poisonous and because residues remaining within the goods generate metabolites. Ethylene oxide which has frequently been used until recently has now been found to be carcinogenic and has been outlawed as a pesticide and also as a disinfectant.
Other methods such as gamma irradiation and steam sterilization or treatment with alcohol vapors result in detrimental changes in the treated drugs."
The authors further state that, for hygienic economical reasons, sterilization of the drugs is absolutely necessary and that, therefore, they have been searching for a new process. At that point of time a pressure/expansion method was found to be optimal for pressure sterilization of foods and medicinal plants. As described in another article of the authors W. Pohlen, G. Rau and E. Finkenzeller in the magazine "Die Pharmazeutische Industrie" (Pharm. Ind. 51, 8, 917-918 (1989)) this method is utilized as follows:
"The material to be treated may remain in the original package and is transported into a pressure autoclave on an especially designed transport cart. When completely filled the autoclave is closed. In order to avoid exposure of the drugs to oxygen the autoclave may be evacuated by means of a vacuum pump to a residual pressure of about 200 m bar. Gaseous carbon dioxide is admitted to the pressure chamber from a storage container by means of a control arrangement until the desired final pressure--according to the article 18 bar to 25 bar--is reached. After the required exposure period the carbon dioxide is released. After complete pressure equilization the autoclave is opened and the treated goods are removed."
The mortality rate for damaging insects as a result of this pressure/expansion procedure was in fact found to be 100% to almost 100%. The disadvantage of this method is that not all the insects are destroyed all the time, particularly not their larvae and eggs and that the process requires expensive apparatus and equipment.
It is therefore the object of the present invention to provide a method for the sterilization of dried goods of the type described wherein all damage-causing insects as well as their larvae and eggs are safely destroyed and which may be utilized economically without the need for expensive apparatus which require large investments.